Valve clusters or, respectively, arrangements as a rule comprise several valve units arranged in tandem which for their part possess a principal valve, which is mounted on a base plate having supply and venting duct extending through it or is integrated in the base plate. Such valve clusters are for example described in the German patent publication 4,143,274 A1 or in the European patent publication 0 678 676 B1. Standardized valve units exist, which possess a supply duct for the supply of the principal valves with pressure medium and two pilot supply ducts connected with the supply duct for the supply of the pilot control valves, provided for the principal valves. The pressure medium and the pilot pressure medium are preferably compressed air. The two pilot supply ducts are for example connected by way of linking plate, preferably arranged in series with the valve units, with the supply duct and are necessarily also acted upon by pressure medium when the supply duct is put under pressure. Frequently it is however not necessary to supply both pilot control supply ducts with pressure medium, since for instance for the supply of one of them a single pilot control supply duct is sufficient. If the principal valve is provided with two pilot control valves, the supply may take place by way of a duct branch formed in the principal valve. In order to reroute the pressure medium supply accordingly it is necessary in the case of conventional valve clusters to replace the linking plate by another one, which renders possible a different routing of the pressure medium.